1. Field of the Invention
The present invention relates to a motor car tyre, in particular a tyre intended for motor cars with a low-to-middle engine capacity, for example 1000-1400 cm3.
This type of motor car is used for short trips around town as well as short journeys out-of-town.
2. Description of the Related Art
Usually, the tyres for this class of motor vehicle, in addition to having good traction and braking properties on dry and wet road surfaces, must be able to ensure soft handling along urban routes, high mileage, reduced petrol consumption, and acoustic and plastic comfort.
Motor vehicle tyres with a tread which has blocks delimited by circumferential grooves, extending in a substantially longitudinal direction, and transverse grooves, extending in a substantially axial direction, are known. The blocks resulting from the intersection of these grooves have suitably designed varying forms and are arranged in adjacent circumferential rows, each of which is situated between two successive circumferential grooves.
The circumferential grooves may influence the steering and travel stability characteristics of the tyre in connection with the lateral (drift) thrusts directed parallel to the axis of rotation of the tyre.
The transverse grooves, in turn, may influence the tractional properties of the tyre, namely its capacity to transmit to the road surface the tangential thrusts parallel to the direction of travel, during acceleration and braking of the motor vehicle.
The circumferential and transverse grooves may also influence the water drainage in the area of contact with the road surface (contact area) during travel on a wet road surface.
JP 10-278512 describes a tyre for high-performance vehicles, provided with a circumferential central rib, circumferential central grooves, rows of central blocks and rows of blocks on both the side portions. The rows of central blocks are formed with blocks which have a circumferential dimension equal to 2 to 4% of the total circumferential length of the tyre, and the rows of blocks on both the side portions are formed with blocks which have a circumferential dimension equal to 1 to 2% of the circumferential length.
The rows of blocks on both the side portions are provided with grooves which are inclined with respect to the circumferential direction. The inclined grooves form obtuse angles with the circumferential grooves on both sides of the blocks.
JP 2004-155416 proposes a motor vehicle tyre and in particular a tyre for a passenger motor vehicle which has different tread pattern portions: in particular, an inner half tread band directed towards the inside of the vehicle and a half tread band directed towards the outside of the vehicle when the tyre is mounted on the vehicle. The total area of the recessed portion of the inner half tread band is designed to be greater than that of the recessed portion of the outer half tread band. The inner half tread band is provided with at least one circumferential groove which extends in a substantially circumferential direction. The outer tread band half is provided with two circumferential grooves which extend in a substantially circumferential direction.